


Definition of ownership

by Askellie (NadaNine)



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Collars, Dominance, Fontcest, M/M, Submission
Language: English
Status: In-Progress
Published: 2016-03-14
Updated: 2017-01-12
Packaged: 2018-05-26 18:07:36
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 6
Words: 14,327
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6250078
Author URL: https://archiveofourown.org/users/NadaNine/pseuds/Askellie
Summary: <blockquote class="userstuff">
              <p>“That your boyfriend outside?” He heard someone ask from inside, the voice low, amused and female. Sans promptly buried his face in his hands, his cheekbones burning with mortification.</p><p>“My brother,” Papyrus corrected indifferently. Sans wasn't sure if the distinction was any more or less embarrassing than her initial assumption.</p><p> </p><p>Papyrus makes sure all of Snowdin knows who his brother belongs to. Sans doesn't get much of a say in this.</p>
            </blockquote>





	1. Chapter 1

Sans has been in Snowdin just long enough to decide it was an okay sort of place as long as he didn't actually have to go out and be in it. The new house was nice enough, at least. It was a far cry from their cramped and crumbling apartment back in the Capital where only the smallest slivers of light managed to creep in through the boards they'd had to nail over the windows, and their door had been smashed in so many times they'd given up and started barring the entry with a lattice of bones to deter any more break-ins.

Apparently those were less common here, though that might have had more to do with the fact that anyone unfortunate enough to live in this backwater outpost probably didn't have anything worth taking. He and his brother certainly counted among that number now. His brother's prized possession was probably his collection of favourite attacks, though any opportunistic thief probably wouldn't find much glory in a musty box of bones. The machine that Sans had laboriously hauled from the Core and stashed in the basement was nothing but a broken wreck, of no use to anyone, least of all himself, but he hadn't been able to convince himself to leave it behind.

The rest of the house was still pretty barren. They hadn't owned much in the first place, and it wouldn't have been practical to haul anything of size across the breadth of the underground even if Sans had been willing to cheat with his shortcuts again. Papyrus had put his well-honed carpentry skills to use and constructed himself a proper bedframe, but Sans had settled on a dirty, threadbare mattress they'd found in the shed and just shoved it up against the far corner of his room, naked of any proper coverings. It wasn't comfortable, but it was functional, and bare as it was, the room was the closest thing he had to a sanctuary since he'd had to leave the Lab.

It was quiet here, unlike the Capital. No screams or sirens, none of the permeating smells of smoke and dust. It did remind him a lot of the Lab, really, where the walls were sound-proofed and the air was kept as cool and and purified by the complex labyrinth of ducts and filters. Maybe that was why he'd been feeling off every since they'd arrived. A strange, melancholy weight seemed to have settled on his shoulders, along with a creeping emptiness that sometimes felt bleak and occasionally veered towards a disconcerting sense of peace, but mostly made him feel like maybe he'd rather just stay in his room forever.

He'd been working on that pretty successfully for the better part of their first week in town, but unfortunately his self-imposed seclusion was doomed to come to an end.

“SANS! GET DOWN HERE. WE'RE GOING OUT.”

Sans allowed himself a deep sigh that thankfully his brother would never hear. He wistfully contemplated rolling over and feigning sleep, but experience had taught him that course of action wouldn't end well. If there was one thing Papyrus hated, it was being ignored.

Reluctantly, he crawled off his bed and laboriously staggered to his feet, wincing at the way his joints creaked and his bones felt heavy with lethargy. He hadn't moved over the last couple of days except when hunger became downright unbearable, and that had involved nothing more than slumping through a shortcut to the kitchen, devouring the first thing he found that looked even remotely edible, and then collapsing right back into bed again. His days had stopped making any sort of temporal sense. He didn't even know what day it was, or what time it was, for what little those details mattered to the incarcerated monster population.

When he opened his door, the light of their living room hurt his eyes. He hadn't really taken much notice, but Papyrus must have been busy over the last couple of days, fastidiously cleaning off all the dirty windows (they had actual intact glass, which was something Sans still found frankly unbelievable) and had even gotten some proper light bulbs to light the interior (which they'd never bothered with back in the Capital since a warm, welcoming interior would just be an invitation for trouble).

Papyrus was standing by the front door, arms crossed and foot tapping impatiently. “SANS!”

Sans blinked sluggishly at him, a frown settling on his face as he grudgingly tromped down the stairs. “I'm comin' already. Sheesh.”

“TOOK YOU LONG ENOUGH,” Papyrus scoffed. “YOU HAVE NO EXCUSE FOR SUCH LAZINESS. YOU HAVEN'T EVEN DONE ANYTHING ALL WEEK.”

It was true enough, and Sans did his best to quash the small pang of guilt that tried to rear its head. It wasn't as if Papyrus had really needed him for anything, after all. In fact he'd rather pointedly told Sans there was no point in him getting involved, believing (probably rightfully) that Sans would somehow manage to fuck up if entrusted with even the barest scrap of responsibility. Papyrus had taken care of pretty much everything that had needed to facilitate their relocation, and Sans might have resented his brother's overbearing management of the whole thing if he didn't feel so damn grateful not to have had to do any of it himself.

“Fine,” he conceded, albeit as belligerently as possible lest Papyrus think he could exploit any undue favours. After all, it hadn't been Sans's idea to move in the first place. “What are we doin'?”

Papyrus lifted his chin, imperiously surveying the far-off horizon at the other end of the living room. “I HAVE CONCLUDED THAT IT HAS BEEN SUFFICIENTLY LONG ENOUGH FOR THE MYSTERY AND ANTICIPATION OF OUR ARRIVAL TO HAVE BUILT TO AN ADEQUATE LEVEL OF SUSPENSE. IT IS TIME TO ANNOUNCE OURSELVES TO THE REST OF THE POPULATION SO THEY WILL KNOW WHOM THEY HAVE TO FEAR.”

Sans's already flagging enthusiasm for the outing plummeted lower than he would have thought possible. His shoulders slumped, posture curling in on itself. “Really?”

He didn't need to even ask. He knew his brother was being perfectly serious.

“OF COURSE. WE HAVE ONLY A BRIEF WINDOW IN WHICH TO MAKE THE OPTIMUM IMPRESSION. MOVE TOO SOON, AND WE WOULD LOOK DESPERATE AND WEAK. MOVE TOO SLOW AND THEY WILL THINK WE'RE AFRAID. THE TIME TO STRIKE IS NOW.”

There was a certain sort of logic in that, even if Sans wanted to believe his brother was over-thinking this. He released a surly sigh. The last thing he wanted to do was spend the day posturing aggressively, trying to convince the townsfolk he was dangerous enough not to mess with. His brother was good at it, given that he had the strength to back it up, but if anyone bothered to check Sans's HP the day would turn into a dusty mess real quick. Of course, a few brutal take-downs would just cement their reputation all the faster, and that would only work in their favour, but Sans didn't enjoy the necessity of it. He tried to convince himself that his objection was grounded in laziness rather than conscience.

“Are you sure it's a good idea to take me along, Boss?” he tried, hoping his expression looked suitably sincere rather than stressed. “You'd probably do a much better job on your own. I'd just slow you down. Wouldn't wanna make you look bad.”

Papyrus just smirked at him, an unexpectedly shrewd glint in his eye sockets. “I HAVE ALREADY ACCOUNTED FOR YOUR INADEQUACY. NEVER FEAR, BROTHER, FOR I HAVE ALREADY DETERMINED A ROLE FOR YOU TO PLAY. IT IS ONE THAT EVEN SOMEONE OF YOUR FEEBLE CAPABILITIES WILL BE ABLE TO PERFORM. I THINK YOU WILL EVEN ENJOY IT, SINCE IT MOSTLY REQUIRES YOU TO DO NOTHING AT ALL.”

Sans found that statement far from reassuring. He eyed his brother warily, resisting the urge to back away from the expression of fearsome intent on Papyrus's face. “What is it?”

Papyrus pulled something from his belt and with a grand sweep of his arm presented it to Sans. “I WILL REQUIRE YOU TO WEAR THIS.”

Sans stared at the proffered item. His jaw worked soundlessly for a few moments, his throat choking on confused syllables until he finally managed to string together the words he was looking for. “What the fuck is that?!”

“HAVE YOU NOT SEEN ONE BEFORE?” Papyrus leered at him mockingly, darkly amused by Sans's outraged bewilderment. “THEY ARE QUITE COMMON HERE, APPARENTLY, SINCE A LARGE FACTION OF THE POPULATION ARE DOGS. THEY HAVE QUITE A SYMBOLIC SIGNIFICANCE.”

“I am not wearing a fucking collar,” Sans spat vehemently, but as always he felt a rush of cold fear whenever he dared attempt to argue with his brother. His body was already locking in tension, bracing for the promise of pain.

“YES YOU ARE,” Papyrus corrected smartly, stepping forward, right into Sans's personal space, and even though Sans flinched he couldn't force his limbs into action. Moments like this made him painfully aware that his fight-or-flight instinct was completely fucked up, rendering him worse than useless. It couldn't seem to figure out what it wanted him to do, so he just ended up stuck, immobilised and completely open to attack. Not even Papyrus's valiant attempts to train it out of him had rendered any effect. In fact, he had a feeling Papyrus had somehow made it all that much worse, because his brother brought him both protection and pain and he never knew which one to expect at any given time.

Despite his expectation of the worst, however, Papyrus simply took advantage of his paralysis and with precise and distractingly graceful motions he fastened the collar around Sans's neck. He didn't even close it too tightly, though there was definitely no way Sans could slip it over his skull. It sat heavy and unfamiliar on his collarbones, and even though it couldn't have strangled him even if Papyrus had clinched it right up to his vertebrae, he suddenly found it much harder to breathe, to think.

“What the fuck,” he wheezed, reaching up mindlessly to tug at the buckle, to get rid of the blasted thing, but Papyrus easily batted his hands away and pointedly tugged on the leash that had been fastened to one of the collar's studded rings.

“LEAVE IT,” Papyrus warned, with just enough ice in his tone that Sans shuddered. His body knew what that particular note of discipline in his brother's voice would lead to if he persisted. His arms unwillingly dropped back to his sides. Papyrus seemed pleased by this implied acquiescence. “COME. WE'RE GOING.”

Another tug on the leash pulled Sans forward half a step, jostling him enough that his outrage came back in full force, spluttering and gasping around tight pants of fury. “I am not...fucking...going out like this-! Papyrus!”

Calling his brother by name was definitely a mistake, and in the next moment Sans was hauled up by the new and convenient hold offered by the collar and slammed with careful force into the wall next to the door. There were times it still amazed him that Papyrus could be so precise with his strength, to inflict pain on his brother without jeopardising his single hit point, but awe took up a distant fraction of his attention compared to the agony jolting through his spine and ribs. Papyrus was holding him up at his own eye-level. Sans's feet dangled well above the floor, and he convulsed weakly, scrabbling at his brother’s hand to loosen the stranglehold without success.

“ENOUGH,” Papyrus hissed, low and dangerous, and Sans promptly forgot how to do anything except quiver uselessly in his brother’s hold. “I HAVE MORE THAN INDULGED YOUR LASSITUDE SINCE WE ARRIVED, BUT MY PATIENCE IS AT ITS END. IF YOU WISH TO PERSIST IN BEING A PATHETIC COWARD THEN I WILL KICK YOUR USELESS HIDE OUT OF THIS HOUSE, AND WE WILL SEE HOW LONG YOU LAST WITHOUT MY PROTECTION.”

Sans whined, high and desperate. “N-no, please, Boss, don’t! I'm sorry!”

“YOU SHOULD BE,” Papyrus growled, twisting his hold enough to make Sans arch in pain, but Sans knew better than to try fight him any further. They both knew kicking Sans out on the streets was tantamount to a death sentence, by murder or exposure or simply his inability to function like a proper monster and actually take care of himself. “I'M FAR TOO LENIENT WITH YOU.”

Sans struggled to nod in fervent agreement, because it was only the truth. For all his brisk and sometimes brutal treatment, Papyrus was remarkably tolerant of his dead-weight of a brother. Sans was more aware than anyone of how lucky he was. His compliance must have seemed contrite enough to appease his brother, since Papyrus deposited him none-too-gently back on the floor, giving Sans only a moment to regain his balance before pulling on the leash again. This time Sans allowed himself to be dragged along, meek and silent, anchored by his brother’s forceful grip.


	2. Chapter 2

Their first stop was a little store on the far side of the town. It wasn’t a terribly long walk, a testament to how tiny a town Snowdin really was, but Sans felt the effort of every step as his bones quavered with taut distress.

Everyone was _staring_.

No doubt at least part of that was due to the natural curiosity and wariness elicited by newcomers. Not to mention Papyrus did cut a very eye-catching figure with the dark, dramatic silhouette of his armour, but Sans was finding that very little consolation because he was quite sure the collar and leash were also drawing more than a few smirking looks and he wanted nothing more than to sink down into a snowdrift and cease to exist. 

Papyrus, of course, was utterly unperturbed by any of it. In fact, there was a certain theatrical flair to each of his movements that told Sans he was aware of all the attention and was enjoying it immensely. Sans couldn’t fathom it in the slightest.

Papyrus paused briefly at the doorway to the store, stomping snow from his boots in a manner that was more fastidious than polite, and turned to consider his brother. After a moment he nodded to himself, and then fastened his end of the leash to one of the window bars, securing it with an easy knot.

“STAY,” he told Sans rather unessesarily, and then imperiously entered the building without him, leaving his brother alone outside in the cold, tethered to the wall like he was some sort of fucking animal.

Now he couldn’t even hide behind Papyrus and pretend people were gawking at his brother instead. Sans huddled up against the side of the building, taking shelter from the chill wind and the judging stares alike.

“That your boyfriend outside?” he heard someone ask from inside, the voice low, amused and female. Sans promptly buried his face in his hands, his cheekbones burning with mortification.

“MY BROTHER,” Papyrus corrected indifferently. Sans wasn’t sure if the distinction was any more or less embarassing than her initial assumption.

“You always keep him on a leash like that?”

The windows of the store were frosted with ice and a layer of grime not unlike what Papyrus had laboriously scrubbed from their own house. If he squinted, Sans could barely make out the figure of the lapine storekeeper leaning against her counter, arms crossed as she regarded Papyrus with heavy-lidded eyes. Papyrus seemed entirely impervious to her blatant interest, examining her wares with sharp attention.

“HE IS VERY POORLY TRAINED,” Papyrus replied, his attention suddenly shifting not towards her, but towards the window as if he could sense Sans’s gaze. Sans muffled his yelp and ducked back out of sight, but kept his ear pressed to the thin wall of the building. “I FIND IT TO BE THE EASIEST WAY TO KEEP TRACK OF HIM.”

“Fair enough,” she said, and thankfully that seemed to exhaust her interest on the matter, or perhaps she had something more important on her mind. Her voice subtly dropped an octave, forcing Sans to strain to hear her. “What about yourself? Rumor has it Captain Undyne sent you out here.”

“NORMALLY I ABHOR RUMORS, BUT IN THIS CASE YOU ARE CORRECT.” Sans could hear the sounds of his brother’s boots clicking on the wooden floor, and a rustle that suggested he was making his selection from the shelves. “I HAVE BEEN SENT TO COMPLETE A SPECIAL TRAINING REGIMEN BEFORE FORMALISING MY ACCEPTANCE TO THE GUARD.”

“Training,” the storekeeper repeated, clearly skeptical. Sans couldn’t blame her, and he’d actually watched Undyne deliver that news to his brother’s face.

“THAT’S RIGHT,” Papyrus’s steely tone warned against any further comment, and the storekeeper wisely didn’t press it. There was a thump of goods hitting the counter. “I WILL TAKE THESE.”

Sans wrapped his arms around his ribs, listening to the jingle of gold as money changed hands. For all he knew, this was the only store in town, which meant every word Papyrus had said was going to be repeated back into the ear of every other person in Snowdin over the next week. Information was a currency of its own, after all.

Anyone even remotely familiar with Undyne and her reputation would see through the farcical ‘training regimen’ she’d gleefully thrust on Papyrus, just as Papyrus himself had. At least he’d had enough self-control to swallow his rage until out of her sight, releasing it only in private and nearly decimating what had been left of their apartment back in New Home, forcing their move to be as immediate as it was inevitable. Sans had been the unfortunate witness of the aftermath, and if he hadn’t nursed a healthy terror of his brother previously, he certainly did now.

There was no such thing as a probationary period for the Royal Guard. You were either in, or you were out, or else Undyne was making a point to fuck with you. Sending a prospective recruit to Snowdin suggested that the unfortunate recipient of her ire was powerful until not to warrant an immediate rejection, but problematic enough that she had to be careful in her handling. Either way, everyone would know Papyrus had caught her attention, and that was, in a way, its own sort of protection. No one would want to destroy the object of her amusement until they were sure she really wanted to get rid of him. 

Mulling over this, Sans came to the belated realisation that Papyrus had really put a lot of thought into this little outing. Perhaps it shouldn’t have come as such a surprise, but given how livid Papyrus had been at the posting, he’d half expected his brother to still be reacting on nothing but rage and instinct. Not this shrewd thinking, planning, maneuvering creature that might very well come to rival Undyne not just in power but in the ability to manipulate others to his own ends.

His brother really was kind of amazing.

Although even this newfound respect for his brother’s intellect didn’t give Sans any insight into the necessity of the collar. He gave the leash a baleful glare as Papyrus exited the store, now holding a tall bag of supplies. He promptly shoved his burden into Sans’s arms instead, and quickly released the knot on the leash to return it to his possession. 

Sans couldn’t tell if the narrow once-over Papyrus gave him was a silent admonishment for peeking in the window, or was just to assure himself Sans had managed to keep himself in one piece for the five minutes or so they’d been apart. Either way, he didn’t say anything except, “COME.”

Resignedly, Sans hefted the bag into a more stable hold and obediently followed.

The sight of movement on the road ahead made him turn his head down, instinctively shifting closer to Papyrus and the security of his nearness. A couple of monsters were milling around outside a building that smelled potently of smoke and salt and something warm and greasy that made Sans’s non-existent stomach twinge with want. Even at this early hour of the morning, bright welcoming light poured out the front window, and the dull thrum of music could be heard from within. 

Papyrus’s long, purposeful steps slowed slightly. Sans cast an alarmed glance up at his brother, and then, furtively, towards the other monsters. He nearly flinched when he realised the marks on their armour identified them as members of the Canine Unit, the most well-known contingent of the Snowdin guard. This town was their territory. Sans had heard the stories of what happened to those foolhardy enough to try and oust them. 

The macabre irony was not lost on him that he and his brother would make a delightfully boney snack for the town’s resident pack of savage dogs. He’d hoped valiantly that they wouldn’t have to face this particular confrontation any time soon, but he could tell from his brother’s posture that this was an opportunity he couldn’t let pass.

Papyrus slowed to a stop, facing off against the dogs. There were three of them. One was lazily propped against the outside of the bar, a small pile of charred dog treats at his feet and another still smoking but hanging forgotten from the side of his jaw. The other moved in eerie synchronous, turning near-identical dark expressions towards the Skeleton brothers.

Sans did his best not to quake. His arms convulsively tightened on the bag, creating a sharp crunch of sound that instantly drew three pairs of canine eyes towards him. His breath lodged in his throat as he felt the familiar beginnings of paralysis taking hold. His thoughts whirled in panic, wondering whether his brother would expect him to fight, whether he could actually concentrate enough to bring his magic to bear, whether the leash would get in the way, _fuck fuck_ , why did he have to do that, he was so screwed-

But oddly enough the dog’s gazes slid right off him after a moment, turning right back to Papyrus. His brother was the bigger threat, after all, but Sans still found that strange. Normally other monsters pegged him as the weak one, the easy target, and tended to lash out at him first. It was a common mistake to give Papyrus an opening like that, which his brother had readily exploited on multiple occasions. Sans had started to think the only reason his brother took him on these little ventures was to act as a juicy piece of bait to the overconfident, seeming not to care that it would only take one stay hit to turn Sans to dust. 

The dogs seemed to know better, however, or maybe they just looked at things differently. Maybe Papyrus looked more appealing to them, the bones of his midriff tantalisingly on display for hungry canines. Sans watched in fascinated horror as one of the dogs’ let their lips curl in a silent snarl, displaying sharp fangs still stained with the bloody tint of their last meal.

Papyrus didn’t so much as flinch. His body language spoke of nothing except unimpeachable confidence. No words were exchanged, but the tension in the air was thick enough to cut with a knife, and Sans could feel it tempering to breaking point well before he was ready, his body locked with the conflicting impulses to run and to fight and to beg his brother to leave and to flare furiously at the dogs and hope they might flee instead, and--

One of the dogs, the female, made a sharp sound that was somewhere between a woof and a scoff, pointedly turning up her nose and hefting the weighty battleaxe she had strapped to her shoulder before stomping back into the bar. Her two male companions exchanged a sour, disappointed look before wordlessly moving to follow, leaving the street empty once more.

Had....had his brother just stared down the Canine Unit?

“HMPH,” Papyrus huffed, sounding disdainful yet satisfied. He turned to leave, needing to pull hard on the leash and practically drag Sans the first few feet before the shorter skeleton managed to figure out how to make his legs work again through the haze of bewildered relief.

He was unspeakably grateful that they didn’t see anyone else on their way home...not that anyone else would have been brave enough to look Papyrus in the eye after that little display. Sans only did so by accident, unable to stop staring at his brother as Papyrus turned and finally, finally, moved to unclip the leash now that they were back in the relative privacy of their house.

Papyrus scowled at him. “WHAT IS THAT EXPRESSION?”

Sans flinched a little, hastily averting his eyes, his jaw working soundlessly for a moment before deciding on the safest answer. “N-nothin’.”

That earned him a distrustful glare, but nonetheless Papyrus reached down and deftly unbuckled the collar from his brother’s throat. Sans blinked, feeling grateful but oddly bereft at the same time. He hardly had a moment to adjust before Papyrus snatched the bag of supplies out of his arms and stalked off to the kitchen to unpack them. 

Sans nearly followed for half a step, forgetting for a moment he wasn’t tethered to his brother’s side any more. He caught himself a moment later, one hand reaching aimlessly into the space his brother had occupied a moment before that was suddenly empty. He’d been dismissed without so much as a word.

That made him feel...something, but he ruthlessly shoved the feeling down, turning away with a disgust that was mostly directed at himself. He should have said something, maybe. _Good job, Boss_. Something to let his brother know Sans understood what had happened, even if he’d been nothing but a useless bystander to the whole thing, but it was too late now. Papyrus would probably just laugh at him anyway. What good was a compliment from someone like Sans?

Since Papyrus didn’t seem to have a use for him any longer, Sans hunched in on himself and began heading up the stairs to return to his room, thoughtlessly running his fingers over his neck bones where the weight of the collar had rested.


	3. Chapter 3

**Notes for the Chapter:**

> So very sorry for the long delay in updates! Have two chapters of snarky, brotherly goodness to make up for it. :)

_**KNOCK KNOCK KNOCK.** _

The thumping impact seemed to rattle the whole house, and Sans sat up on his mattress with a jerk, his eye sparking, dyeing his vision crimson and sending a painful jolt through his skull. He stayed frozen for a few moments, trying to identify the threat, half-expecting the sound to be followed up by Papyrus angrily forcing his way into Sans's room.

Though come to think of it, Papyrus probably wouldn't even have knocked.

True enough, the next thing he heard was his brother's stomping footsteps heading down the stairs towards the front door. The walls did little to muffle the force of his voice as he opened it for whoever had knocked with such force. “WHAT?”

“'SUP LOSER!”

Oh _god_. It was Undyne. The knocking probably should have tipped him off. Sans made an executive decision to faceplant back onto the mattress and cover his skull with his blanket to try and pretend this day wasn't happening. He definitely wasn't going out there even though he could feel the urgent impulse to go watch his brother's back. It wasn't like he would really be able to stop her if she decided to dust Papyrus, and he'd found that the two of them in close proximity created such an atmosphere of murderous intensity it actually made him feel physically ill. Worse, both of them seemed to get a perverse sort of enjoyment out of it.

Papyrus might call Sans a lazy coward, but Sans was sure Papyrus had some kind of a deathwish in the way he'd persistently badgered Undyne about letting him into the guard until she'd eventually exiled them out here on the tenuous excuse of 'special training'. Sans had faintly hoped that maybe she would start to forget about them now that Papyrus wasn't determinedly planting himself outside her house, but apparently he was shit out of luck. 

Even the extra layer wasn't quite blocking out the resounding boom of their voices...until suddenly it went starkly silent. Deathly silent. Sans was lunging out of bed and stumbling towards the door before he could stop himself. He very nearly crashed into the banister, hearing the old wood creak warningly under even his slight weight. “Boss!?”

Papyrus was standing at the front door, now closed, looking down at something in his hands. Undyne was gone, thankfully, but if anything the tension in the room that Papyrus was generating all on his own was thicker now. More menacing. Sans had to resist the urge to flee back into his bedroom again. Something was wrong. His soul twisted.

“Boss?” he tried again, softer this time, warily moving to descend the stairs. 

Papyrus half-turned, his face unnaturally void of expression, and whatever Sans had expected his brother to be holding, it wasn't the harmless sheaf of papers he actually had in his hands. 

He also didn't expect Papyrus to shove it at him the moment he dared to get close enough. “HERE.”

Sans fumbled, nearly dropping it, and needing a moment to crumple it and flatten down the small tears Papyrus's clawed gloves had pierced through it. The damage wasn't enough to mar the blood-red seal of the royal family on the top corner marking it as an official document. 

He read it quickly, eyes devouring the words, but somehow after three repetitions they still made no sense. His brow furrowed, eyelights shrinking with concentration. “This uh...it's...”

_...application has been successful, and effective immediately you will begin your assignment. Please find enclosed the details of your post and the duties..._

“She made you a sentry,” Papyrus said, voice low, and unlike his expression, there was a whole host of emotion in his voice, so convoluted and thick Sans couldn't even decipher it all. “She made YOU a sentry.”

Sans stared numbly at the paper again and, yes, that was indeed what it said in fairly simple, straightforward terms, but Sans struggled to wrap his head around it. He was damn sure he had never submitted the supposed application, having no interest whatsoever in a job that pretty much guaranteed he'd be put in harms way at some point or another, and what the hell did Undyne think she was doing!?

Oh. OH. And suddenly Sans got it, as Papyrus's face twisted in rage and pain and he very suddenly and deliberately lashed out and smashed one bony fist into the wall, causing a crack. Sans stared at it, wondering for a moment how much control it had taken for Papyrus to aim there instead of at Sans's head. 

“SHE...” Papyrus snarled, obviously struggling for composure. “MADE YOU...”

And she'd obviously come to deliver the news herself, just to rub his face in it. Everyone knew sentry positions were just a stepping stone to becoming a full guard. Hell, to have a post in Snowdin was probably the next best thing to guarding the palace itself, because when (if) the next human came through, the _last_ human, Snowdin's sentries would likely be the first to know. 

Say what you would about the dogs, but one of the reasons Asgore let them have the town largely without supervision, was because they were _loyal_. And if Papyrus had been given that measure of trust...well, he would have been insufferable about it, but Sans knew better than anyone that Papyrus would have delivered any human to Undyne tied with a pretty ribbon just to show her that her faith had not been misplaced, that he would be devoted to her if only she would give him the chance...

But she hadn't. She had deliberately overlooked his eager, hungry, capable younger brother to give the position to Sans who was possibly the least suited monster in the underground (well, maybe he was slightly more suitable than a Moldsmal, but not by much) just to deliberately spite Papyrus and crush his dreams beneath her armoured heel. 

Sans didn't tend to feel too strongly about things these days, but that actually kind of pissed him off a bit. He'd let it simmer in the back of his mind for a while to see whether he actually felt like doing anything about it.

“Don't worry, Boss,” he soothed hastily, shoving the paper into his pocket, out of sight. “I'm not gonna-”

“YOU'LL DO IT,” Papyrus hissed, his tone brooking no argument. “SHE WON'T LET YOU REFUSE, AND...I WON'T LET HER _WIN_.”

“Sure,” Sans agreed quickly. Anything to appease his brother. “Fine. I'll take it, but...”

He trailed off, not entirely sure what to say that might wipe that look off his brother's face. He was almost willing to say something purposefully stupid just so his brother would look angry instead of...wretched. Fuck. Papyrus should never look like that. 

Though thankfully it didn't last long. Papyrus visibly gathered himself and straightened his spine, jaw clenched and eyes narrowed as he finally turned his gaze away from the crack in the wall to Sans. Sans resisted the urge to shiver as he brother looked him up and down (that short, unimpressive span) with hard judgement in his eyes that made Sans think about what exactly he'd just agreed to. 

Shit. Why the hell did he have to go ahead and say that? Then again, it would take more courage than he possessed to turn his brother down in the face of that awful expression. Or to tell Undyne to shove off. That was a quicker way to get dusted than just taking the damn sentry position. 

“YOU START TOMORROW,” Papyrus told him, proving he'd examined the paper more thoroughly than Sans had. “WE SHOULD INSPECT YOUR POST TO ENSURE IT IS PROPERLY FORTIFIED AGAINST INTRUDERS.”

Sans was pretty sure that was something he could sort out tomorrow when he actually _started_ the damn job, but one look at Papyrus's stern expression made him bite down his instinctive objection. “Okay, I can just-”

A glare shut him up and belatedly reminded him that Papyrus had said _we_. No chance of just going out for a while and pretending he was looking the outpost over. Sans grudgingly descended the last few steps and approached the door. Papyrus pulled a looped coil from his belt that Sans needed a moment to identify, to his grief.

“Oh come on, Boss,” he pleaded, because he'd agreed to all the rest with barely a mutter of complaint, but did he _really_ have to wear the collar again?

Apparently so, because his brother moved to fasten it, completely ignoring Sans's muted whine of frustration. Sans managed not to flinch even though there was a splinter of wood in his brother's glove that grazed the edge of his jaw as the collar was tightened. Today was not a day to test his brother's patience. Besides, Papyrus looked a little better once the collar was on. He seemed more assured, somehow, as he pulled the leash to force Sans to keep close as they departed out into the cold of Snowdin.

Sans sighed. He could already tell it was going to be a long day.


	4. Chapter 4

“THIS IS COMPLETELY UNACCEPTABLE.”

Papyrus paced back and forth in front of the sentry station, working himself into a frenzy of distate and unfortunately Sans was forced to move with him, leashed as he was to his brother's wrist. His comparatively shorter legs were having trouble keeping up.

He didn't actually think the place was so bad, but--

“LOOK AT ALL THIS SNOW! HAS NO ONE MAINTAINED THIS STATION?”

“NONE OF THESE PUZZLES HAVE BEEN PROPERLY CALIBRATED! HOW ARE THEY MEANT TO STOP A HUMAN?”

“WHAT IS THIS AWFUL LAMP DOING HERE? WHY IS IT HERE!?”

\--Papyrus felt differently about it.

“Look, it's --heh-- snow problem, Boss,” he said carefully, with just the right amount of deference to balance out the cheekiness. “I'll take care of the station, and--”

“SANS,” Papyrus scowled at him sternly. “DID YOU JUST-”

“--you can take a look at the puzzles. I'm sure someone as en _light_ ened as you won't have any trouble getting things back into order.”

Papyrus tried to stare at him as stoically as possible, but his jaw spasmed just slightly. Sans hadn't gotten a genuine laugh out of Papyrus in years with puns like that, but every so often if he could catch his brother alone and off-guard, he could get those little twitches that were nearly as good as smiles.

“FINE. I WILL ATTEND THE PUZZLES, SINCE THEY WILL REQUIRE A GREAT DEAL OF WORK AND IMPROVEMENT. MUCH LIKE YOU, BROTHER.”

“Sure. You've had lots of practice,” Sans agreed easily, unoffended, and was rewarded with smug 'NYEH' of agreement. 

“VERY WELL.” Papyrus looked at the leash in his hand, considering his options, and then secured the end of it to one of the corner posts of the station. “I WILL RETURN.”

Oddly, it seemed to take a moment for him to follow through with that statement, as if he were reluctant to let Sans out of his sight, but after a moment he gathered himself and strode off with his typical conviction. 

Sans waited until he was very sure his brother was out of earshot before letting out an explosive breath, pent up anxiety shuddering through his rib cage. He eyed the run-down station he was tethered to grimly, trying to convince himself not to loathe it on sight. It hadn't escaped his notice that this station was so much further out than all the others. So much more isolated. He didn't think Undyne knew what his HP was, but she knew he wasn't a fighter. If a human actually came through, well, chances were no one would hear him screaming. If he managed even that much before he dusted. 

“Shit,” he muttered, feeling faintly queasy. Undyne really had it in for them. Or, well, just Papyrus probably, but Sans was gonna get screwed because he was a nice easy target and even though family didn't always mean anything down here, Undyne must have figured it meant _something_ that the two of them were still together. Sans's inertia towards change was one thing, but Papyrus wouldn't still be putting up with him unless some part of him was willing.

Ah, and there was the familiar feeling of guilt to go along with his dread. He stepped up to the station's counter, half-heartedly brushing away some of the thick layer of snow. He gave up a moment later, feeling immensely tired in a way that had nothing to do with the effort he'd just expended, and hated himself a little more for it.

Sourly, he kicked the side of the station just to convey his displeasure, and that turned out to be an extremely idiotic decision because the support struts swayed a little, dislodging the snow on its sloped roof which promptly fell off and buried him. The collar yanked unpleasantly as he went down, leaving him choking as well as spluttering as he dug his skull and an arm free and then decided _fuck it_ he could just lie here in the snow for a while. Maybe he could convince Papyrus he'd gotten stuck to explain why he hadn't cleared the snow like he said he would. 

It wasn't too bad, really. The cold didn't really bother him that much, and his mattress at home was only marginally softer. He let his head fall back, spine contorting a bit oddly to accommodate the position, but he'd slept in worse places and at least out here, unlike in the Capital, it was quiet. 

At least until someone trod rudely on a stick, snapping him out of his doze. It couldn't be his brother. Too subtle. Instinct held Sans still until he could assess the threat, so he carefully rolled his eye backwards until he could see the figure shuffling around the station.

It was one of the dogs from yesterday; the one who'd been smoking. He was scuffing back and forth over the tracks the skeleton brothers had left, sniffling audibly. Sans just watched him for a minute that stretched longer, becoming more awkward as the dog just studiously ignored him despite how on-edge it looked, ears pricked and swivelling back and forth as it went about its business.

Eventually Sans couldn't take it any more, and blurted, “What are you even doin'?”

The dog startled with an audible yip, drawing a pair of knives and swivelling its head back and forth. “Who said that!?”

“Uh...” Sans blinked, and the dog squinted in his direction as if trying to figure out where his voice was coming from. Sure, he was still half-buried in the snow, but he wasn't exactly hidden from sight. Couldn't it see him?

Moving cautiously just in case it decided to put those knives to use, Sans slowly dug himself out of the snow pile, and only once he started moving did the dog's narrowed eyes finally settled on him. It looked disgruntled. “What were you doing there?”

Sans didn't actually have a good answer for that, so he instinctively glowered and snapped back, “What were _you_ doin' sniffing around like that?”

“Trying to figure you out. This is the edge of my station's territory,” the dog said, starting to squint again, like it was having trouble focusing. “You the new sentry?”

“Yeah,” Sans admitted grudgingly. The dog must be assigned to the last station he and his brother had passed on the way out here. 

“Figures,” the dog grumbled. It sheathed its knives, which was something of a relief, but then immediately stepped closer which wasn't. Sans froze, his legs feeling rooted to the spot as he tried to decipher those conflicting signals. 

“ _Now_ what are you doin'?” he asked, hoping the dog hadn't picked out the slight quaver in his voice. Even if he wanted to step back, the length of the leash wouldn't let him go far, and doing so now would only be taken as a weakness.

“Learning your scent. Easier to recognise you next time,” the dog informed him, blatantly huffing its snout against the front of his jacket. That was...well, discomforting, but not exactly threatening. He flinched a little when it nosed the taut length of the leash, wondering if it might suddenly spring an attack now that it could tell he was at a disadvantage. He'd figured out there must be something wrong with its eyes since it only seemed to be able to fixate on anything that was actively moving, but the only comment it had about that little discovery was a grumbled, “Lucky.”

What?

Sans wanted to ask what the hell it meant, but the dog was already stepping back, sniffing the breeze. “Where's your Alpha?”

It took Sans a moment to figure out what the dog was looking for, and then he scowled. “You mean my brother.”

The dog gave him a blank look. “That's what I said.”

This conversation was starting to give Sans a headache. 

“He's...close,” he hazarded evasively, wondering suddenly if this dog was the only one listening. Maybe he was just the vanguard of the rest of the pack, getting ready to spring a trap. “He'll be back in a minute.”

But the dog just nodded. “Good. Better you don't stray too far. Even with that collar, someone else might try to claim you.”

That was a strange way to talk about dusting someone...if that's even what he was talking about. Sans reached up to pluck at the leather around his throat, brow furrowed. “What do you mean?”

The movement of his hand drew the dog's gaze, and it offered him a toothy smile. “You don't need to worry about the guard, at least. Everyone there knows what it means. But some of the others...”

“SANS!”

Both Sans and the dog jumped, startled, but despite its volume Papyrus's voice was still some distance away. Apparently Sans's wild guess about his brother's return hadn't been too far off after all. 

But the dog's ears were flattened and it definitely didn't seem keen to stick around even though Sans was burningly curious about what it meant by 'others'. “I gotta go.”

“Wait-” Sans started, but didn't even get a chance to finish before the dog bounded off towards the trees, hastily vanishing from site just as Papyrus stomped back into the clearing. 

“I CANNOT FATHOM HOW THESE PUZZLES COULD HAVE REACHED SUCH A POOR STATE OF REPAIR,” Papyrus complained immediately, his gloves showing stains of sap and grease. “I WILL NEED SIGNIFIANT TIME AND RESOURCES TO--”

He paused suddenly, staring at Sans's expression and seeming to sense something amiss. “WHAT?”

“Uh...nothing, Boss,” Sans assured hastily, because he was pretty sure his brother wouldn't like to hear he'd been fraternising with one of the dogs even if they were technically co-workers now. He also wasn't entirely sure how to approach his brother with the question of exactly what had compelled him to put the collar on Sans in the first place and what it even meant. He was starting to realise there was more to it than a means of keeping his brother on a very short, literal leash. “We done for the day?”

“I SUPPOSE,” Papyrus allowed, stalking forward to untie his brother. “I WILL NEED SOME SUPPLIES BEFORE I CAN CONTINUE. DID YOU KNOW THERE ARE NOT EVEN ANY SPIKES IN THE TRAP PIT? UNBELIEVABLE.”

Papyrus could rant at considerable length about proper trap design and maintenance, and Sans was comfortable letting the words roll over him as he allowed himself to be pulled along, watching the hand that held the end of his leash with a firm, possessive grip.


	5. Chapter 5

Papyrus was aggravatingly insistent that Sans take his new Sentry position seriously, even though he vehemently didn't want to. His vague notion of taking a long overdue vacation in Snowdin to try and get his head sorted out was torn to shreds, because not only did Papyrus drag him out of bed each morning, but he also insisted on walking Sans to his station on that fucking leash for every shift.

And humiliating as it was, he was also at least a tiny bit grateful, because to get to his station he had to get past the outposts of other members of the Canine Unit, and having his brother with him seemed to keep their aggressions limited to a lot of ugly snarling and glaring. Whatever 'optimum impression' Papyrus had made on that first day apparently intimidated them enough to not want to approach the taller skeleton. Sans was still bewildered but reluctantly impressed by his brother.

Only once Sans was at his station was he allowed 'off the lead'. Unlike that first day, he didn't tend to hitch Sans to the post just in case he needed to actually do his job. Instead he'd coil the leash into a loop, attach it to his belt and take it with him into the woods when he went off to attend the puzzles which had become Papyrus's self-appointed responsibility ever since he'd found them in such a terrible state of disrepair.

And whenever he was gone, Sans would find his fingers tugging and twisting the collar, yanking it restlessly but never daring to remove it. He _could_ , if he wanted. Papyrus was usually gone for hours, and even on the few instances where he'd come back to check on Sans (to make sure he wasn't sleeping on the job – that had only happened once!) he made enough noise that there would be plenty of warning.

Papyrus hadn't even explicitly told him not to remove it, it was just...

Whenever he wore it, the dogs almost acted as if he were invisible. Of course, they might have done that anyway – Sans hadn't exactly had the opportunity to walk around without it to test out their reactions – but the guard from his neighbouring station whose name turned out to be Doggo had seemed to imply that there was something of particular significance about the collar to the dogs in particular. Sans wasn't willing to risk whatever veneer of protection it seemed to be giving him just in case another member of the Guard happened to pass through when his brother was absent.

Though so far he hadn't had any other visitors. No humans, thankfully, though the actual likelihood of one passing through was practically non-existent – Sans could probably have figured out the precise probability if he'd cared enough to crunch the numbers. Even so, the first day that Papyrus removed the leash he'd hesitated for an inordinately long time in uncoupling the clip from the collar's ring.

“IF AN ACTUAL HUMAN SHOWS UP...” Papyrus had said, and then stopped, looking like he was choosing his words carefully. After a few seconds he'd shaken his head as if dispelling his uncertainty, and straightened with a hard scowl on his face. “MAKE SURE YOU LEAD THEM TOWARDS MY TRAPS. IF I CAPTURE THE HUMAN THEN NOT EVEN UNDYNE WILL BE ABLE TO PREVENT ME FROM JOINING THE GUARD. DON'T SCREW THIS UP FOR ME, BROTHER.”

Sans had been quick to agree, not only because he hadn't wanted to stretch the awkward moment any further, but because the order had come as something of a relief. If this was Papyrus’s latest idea to impress Undyne, it was a hell of a lot better than his previous scheme to stalk her through Waterfall and then camp outside her house from dusk until dawn. If tending the puzzles kept Papyrus distracted and, better still, out of Undyne’s hair, Sans was happy to go along with it even if refusing to immediately report the presence of a human was probably tantamount to treason. He was pretty sure there was a rule about it in the Sentry handbook that he’d only cursorily glanced through.

It kept him out of Sans’s (more figurative) hair as well, which was a welcome change. Sure, Papyrus was the only person left in the world whom Sans might actually give a damn about, but he was also abrasive, demanding and more than a little terrifying. After all those days he’d spent in Waterfall trying to get Undyne’s attention, his LV had gone up dramatically, and Sans was painfully aware of the simmering violence Papyrus hadn’t yet mastered enough to repress. 

If he trusted Papyrus’s control any less...well, he’d like to think he’d be smart enough to leave, but he wasn’t entirely sure that was true.

Strangely enough, the times he felt most comfortable with his brother was when Papyrus was holding the other end of his leash. It seemed to affect his brother’s mood somehow, making him more...smug? Assured? Perhaps the confidence was feigned for the benefit of their onlookers, but whatever it was, Sans could feel the roiling aura of LOVE settling, and only then could he finally relax around Papyrus. 

Work on the puzzles seemed to be helping Papyrus settle that restless itch that drove him to pursue a place in the Guard. Sans ran into him on patrol sometimes and often just stayed silent and out of sight, watching his brother work. Papyrus kept trying to prove himself to be a fearsome fighter – and he was getting better on that front – but his greater passion was for the puzzles and traps that littered the forest. Some were positively archaic, a remnant of the time when puzzles had been intended as more a pleasurable diversion and a test of wits than a true threat and impediment. Even so, Papyrus wasn’t wasteful. He carefully cleaned and refurbished the existing equipment, oiling gears and correcting counterweights and chipping away at the unavoidable coating of ice that covered everything.

Today he was finally adding spikes to the trap-pit he had so zealously complained about. Sans was ostensibly 'helping' by passing his brother each tool as required, but mostly he was just sitting on his tailbone watching Papyrus driving stakes into the ground in some sort of indiscernible pattern. Sans squinted. He thought it looked sort of like a goose, but he was pretty sure that wasn’t what his brother intended it to be.

“Y'know, Boss,” he remarked conversationally, “if a human actually falls in there and dies, we won't, uh, actually get their soul. Seems kinda counter-productive, don't you think?”

“NONSENSE!” Papyrus said with a particularly emphatic twist of the sharpened spear in his hand, angling it _just so_. “NO HUMAN WOULD BE PUNY ENOUGH TO DIE FROM A SIMPLE IMPALEMENT! THIS WILL ONLY SLOW IT DOWN SO THAT I CAN HAVE THE GLORY OF DEFEATING IT IN A PROPER BATTLE.”

Sans wasn't entirely convinced that his brother really knew what a human even looked like, let alone what one was capable of. Most of the humans that had ended up in the Underground had been children, which were significantly more fragile than adults of the species (albeit much less dangerous). He thought about whether he should remind Papyrus of that fact, but he didn't think the knowledge was actually widely known, and his brother might question how and why Sans knew so much about the Fallen Humans. That was definitely not a conversation he wanted to have. 

“BESIDES,” Papyrus continued, unprompted, his brow furrowed in concentration. “IT IS HIGHLY UNLIKELY A HUMAN WOULD BE APPROACHING YOUR STATION FROM THIS DIRECTION. MOST OF THEM HAVE TRAVELED FROM THE PATH TO THE RUINS, CORRECT?”

“Uh...yeah,” Sans said, blinking and wondering if he was reading too much into it that Papyrus had phrased it that way. He wasn't concerned about a human heading for the town...or rather, he wasn't arming the pit against the possible invasion of a human at all, since his statement was correct. Humans would most likely be coming from the other direction. The pit was situated on one of the narrow paths that approached his station from behind, and so the most likely threats from that direction would be-

Other monsters. Papyrus was worried (or at the very least was entertaining the possibility) that someone might ambush Sans from behind. One of their own kind.

“HURRY UP AND PASS ME ANOTHER SPIKE,” Papyrus snapped, breaking Sans out of his reverie. Wordlessly, he handed Papyrus a new stake, suddenly seeing his brother's diligent attention to the traps in a new light. 

An ominous musical refrain sounded from Papyrus's hip pocket. Sans recognised the theme song from Mettaton's latest theme show and didn't quite suppress a snicker. Papyrus studiously ignored him, pulling out the phone to answer it. “YOU HAVE REACHED THE GREAT AND TERRIBLE PAPYRUS.”

“So you're still alive, huh, punk?” Sans could hear Undyne's sneering clearly over the line, even from several feet away. “I'm expecting to hear any day now how they're using your dust to salt the streets.”

“THEN I'M AFRAID YOU SHALL BE LIVING IN PERPETUAL DISAPPOINTMENT,” Papyrus said, apparently undeterred by the high-volume insult. “THE TOWN HAS ONLY IMPROVED SINCE OUR ARRIVAL. FAIRLY SOON OUR DISTRICT SHALL BE THE ENVY OF THE UNDERGROUND FOR ITS ADHERENCE TO ORDER AND SUPERIOR PUZZLE DEFENCES.”

Undyne laughed uproariously. “Puzzles, huh? You're still screwing around with that useless shit? Man, next you'll be telling me your brother is actually doing his job.”

Papyrus made urgent shooing motions in Sans's direction. Sans took the hint and laboriously climbed to his feet, steeling himself for the hike back to his sentry station.

“IT'S OKAY TO ADMIT YOU DON'T HAVE A VERY REFINED SENSE OF PUZZLE AESTHETICS, UNDYNE,” Papyrus offered smoothly, turning away from his brother “YOU HAVE MANY FINE TALENTS. IT'S OKAY IF INTRICATE TRAP DESIGN ISN'T ONE OF THEM.”

There was a meaningful pause, during which Sans decided to put as much distance between himself and the source of Undyne's voice as possible. It was amazing how even speaking coldly he could very clearly make out her reply. “What did you say?”

Damnit. Pap was going to run his mouth and screw them over again, Sans just knew it. Worst of all, whenever he talked to Undyne, it was impossible to ignore the rare note of enjoyment in his tone. Against the odds, his dangerously optimistic little brother actually liked sparring with Undyne, verbally or otherwise. 

Sans didn't get it. More so, it made him feel weirdly aggravated – both protective and possessive, which wasn't at all like him. It was long past the days when he could even pretend that his guidance helped to keep his brother safe. He didn't even try anymore. He knew better than to think he could change Papyrus's mind about the brutal Captain of the Guard, but the compulsion to try kept niggling at him like an itch that he couldn't scratch. He ignored it vehemently as he made his way back to his station, dropping down heavily on the stool and letting himself be distracted by his dark, brooding thoughts.

He was absorbed enough to nearly fall off his chair when Papyrus reappeared not long after, strutting proudly and looking decidedly smug. 

“What's up, Boss?” Sans asked, trying to make it sound casual rather than nervous. These days, his brother looking so pleased didn't always mean something good was about to happen. 

“CAPTAIN UNDYNE MENTIONED SHE MAY HAVE BEEN OVERLOOKING THE POTENTIAL OF THE PUZZLE DEFENCES IN WATERFALL, AND HAS ASKED FOR MY EXPERT INPUT ON BRINGING THEM UP TO CODE!”

“That's...uh...” Now he was wishing he'd stayed to overhear the conversation just so he might have a better idea of what fresh hell Undyne might have in store for his brother this time. “Good?”

Papyrus ignored his dubious tone. “IT IS AN EXCELLENT OPPORTUNITY. I AM SURE SHE WILL REALISE THE VALUE OF MY CONTIBUTIONS IN NO TIME.”

At best, he imagined Undyne was going to use Papyrus as free labour for puzzle repairs much as Papyrus had been using Sans earlier. At worst...well, he would try valiantly not to think of that. As buoyant as Papyrus was now, there was no chance of talking him out of it. “So she wants you in Waterfall? When?”

“RIGHT NOW!” Papyrus crowed. “AFTER ALL, THERE IS NO TIME LIKE THE PRESENT. I SHOULDN'T MAKE HER WAIT.”

The worst part was, underneath the guff and theatrics, Papyrus seemed honestly excited. It made Sans's soul twist a little in both fondness and regret. It was so rare to see that emotion in him, these days. 

“Better not,” he agreed against his better judgement and trying to capture at least a hint of Papyrus's enthusiasm, as if he had no reservations about it. “It's about time she learned what a puzzle genius you are.”

Papyrus scrutinised him for a moment – as if looking for any trace of mockery – and, finding none, offered a rare smile of true pleasure. “I AM CERTAIN SHE WILL REALISE HER FOLLY IN UNDERESTIMATING ME. NYEH HEH HEH!”

Papyrus turned on his heel, marched two steps, and then paused, apparently remembering something. He turned back to Sans. “I MAY BE GONE FOR MOST OF THE EVENING, BUT REST ASSURED, I SHOULD BE BACK BY TOMORROW. IF BY ANY CHANCE I AM LATE, DO NOT MISS THE BEGINNING OF YOUR SHIFT! I WON'T BE AROUND TO WAKE YOU.”

“Sure thing, Boss,” he said, more to put his brother's mind at ease than out of any real commitment to the task. It seemed to work, because Papyrus looked thoroughly satisfied as he strode away, leaving Sans feeling suddenly very alone in the empty woods without the comforting safety net of his brother's nearness. 

He glanced around as if suddenly seeing the woods for the first time in all their shadowed, forsaken glory. 

“Shit,” he muttered, bony phalanges clawing absently at the station's desk as he sat up ramrod straight and alert for the slightest sound. It didn't help knowing what his brother had been preparing the pit trap for, and Sans half-expected to hear some hungry, stalking predator creeping up on him at any time. 

Worse, he fretted over the possibility that he wouldn't hear them coming at all. 

More than once he found himself clinging to the collar like a lifeline. It gave him something to keep his hands occupied instead of clawing up splinters from the wooden table.

It was a long, unpleasant couple of hours to endure until the end of his shift, but thankfully they passed without incident save for the stressful efforts of his own imagination. It was an unspeakable relief when it finally ended, and he was off his chair not one second past his appointed finish time. 

With his brother at his side, Sans was forced to walk the path between home and his station every day, but left to his own devices, there was no reason not to take a shortcut. He superciliously glanced around, making sure he was unobserved (particularly by those sneaky cameras he kept finding in the bushes) and teleported back towards home.

His aim was a little off. It had been a while since he'd practised, and so instead of stepping back neatly onto his own front doorstep, he ended up in the alley next to the shady bar in the middle of the main street.

Sans attempted to look nonchalant as he straightened his coat and stepped out into the open, but already he could feel an anxious sweat condensing over his bones. It was so much easier when all he had to do was hide in Boss's shadow and walk fast enough to keep up with him. On his own, he had to keep his eyes peeled for threats from every possible direction, but particularly from behind. He had to scrutinise every monster he came across for how much LV they had, what their mood was, whether they noticed him, whether they were going to cause trouble...it was exhausting. 

Thankfully the streets were largely deserted, though that may have been due to the contingent of dogs hanging around the front of the bar again. Sans tried not to wince. As much as he'd rather find a long way around, it would be stupid to risk travelling through the backstreets when he still didn't know the town very well. He didn't keep his face down because looking too meek was as good as broadcasting your weakness, but he walked around them at a respectful distance, doing his best to look like he was minding his own damn business.

He kept an eye on the pack out of the periphery of his vision, but even without his brother, they all seemed content to ignore him. Doggo was there again, smoking against the wall, and he was the only one who caught Sans's eye (or something like it – the dog didn't seem to be very good at focusing). He flicked his smouldering dog-treat in a way that might have been like a wave, but otherwise didn't acknowledge him. 

Sans strode past, gaining confidence with each step until he was far enough down the street to acknowledge that he was definitely in the clear.

The damn collar really worked. A part of him had still been convinced that Papyrus's presence was the real reason the Dogs had left them alone so far, but apparently even without him the collar still served its purpose. 

Shit. Pap had really come through for him this time. Sure, it was still humiliating, but a hell of a lot better than being pulled into an actual fight. 

He made it all the way home without incident, and stepped inside with no small amount of relief. The house felt strangely empty without his brother, but he convinced himself it didn't matter. He'd just spend the evening hiding in his room anyway, so it wouldn't make any difference.

Sans headed for the stairs only to pause, feeling strangely like there was something he'd forgotten.

Oh right. The collar. Normally Papyrus took it off in their entryway and put it on the new hook hanging beside their door, installed specifically for that purpose. Sans reached up again, twisting it around so he could reach the buckle. His fingers hesitated over the metal. 

_Take it off_ , he ordered himself. He was inside. He didn't need its protection any more.

He stood there stupidly for almost a minute before he realised he didn't actually want to. It felt wrong for Papyrus not to be the one removing it, and now more than ever having it on gave him a strange sense of comfort. As if it were some magical talisman that would keep him safe until his brother got back.

Which was a stupid thought. _He_ was stupid, he tried to berate himself, but not even his worst self-recriminations could convince him to unfasten the collar.

Sans was too tired to argue with his instincts after repressing anxiety all afternoon. Fuck it, the collar could stay. No one had to know. Papyrus still wasn't home, and Sans could just take it off before morning when he wasn't feeling quite so unsettled. 

The decision was enough to appease his dignity as he stomped up the stairs for a well-earned nap.

**Notes for the Chapter:**

> With the posting of this chapter, I'm going to be opening up drabble prompts for the next week or so. Come check it out on my tumblr at [askellie.tumblr.com](http://askellie.tumblr.com).


	6. Chapter 6

Sans didn't sleep well, most nights. Sometimes it was gnawing anxiety keeping him up, fretting about getting through the next day, protecting their territory, protecting his _brother_. Sometimes it was nightmares, usually of the lab, remembering the dark vortex that had swallowed Gaster up or the expression on his face that moment he'd realised what was happening to him. In those dreams, Sans's imagination recreated the event in great detail the way Gaster's very being had split and bent as if his body was turning inside out, twisting in agony before vanishing into the darkness.

And nothing could drive away his unsettling certainty that somehow, despite that, Gaster was still alive somehow – mutilated and trapped and _aware_. That was possibly the most horrifying part.

The days when Sans actually managed to fall into deeper sleep were rare – practically non-existent since the accident...so of course the one night he somehow managed it his brother had to come and ruin it.

“SANS!”

Papyrus's voice was even louder than usual, but Sans only twitched sluggishly, resisting consciousness with every fibre of his being because noooo, he actually felt peaceful and light and it was so good just to feel the quiet emptiness in his own skull with no horrible images or self-recriminations to ruin it. He turned his face into the mattress, groaning weakly in protest, but unsurprisingly this did nothing to deter his brother. The door to his room was thrown open, and Papyrus's forceful footsteps reverberated through the floorboards.

“SANS, WAKE UP!”

It was a good thing Sans didn't have the instinctive violent reactions of most other monsters, or Papyrus might have been accidentally skewered by bones when he promptly grabbed Sans and simply lifted him from the mattress. Unfortunately Sans's reflexes proved to be as inadequate as ever, and he simply blinked owlishly at his brother, hanging limp and useless and helpless. If it had been anyone else, he would be dust by now, and he wasn't even sure he'd have been able to work up the energy to care.

But of course it was Papyrus, who was...smiling. Beaming, in fact, his fanged visage taking on a strangely endearing quality in his excitement. Sans was used to hearing his brother shout in frustration, in annoyance, in anger...but not in glee. Not with such light, cheerful zeal.

He was still unhappy about being woken, but he supposed that if anything, this might be worth waking up for.

“Huh'wha?” he slurred, trying to relearn how to move again even though he felt almost comfortable just dangling from his brother's grip. “W'sup Boss? You're back...early?”

Ungodly early, if the weak light shining through the window was any indication. At least that meant Sans hadn't slept through the start of his shift which was probably contributing to his brother's good mood.

“YES! MY MISSION WAS A RESOUNDING SUCCESS!” Papyrus was never one for staying still, and Sans found himself suddenly crushed to his brother's chest as Papyrus adjusted to a more comfortable hold and marched out of the bedroom. All the protests that should have been forming from such undignified treatment were blown from his mind because while Papyrus would sometimes manhandle him when overpowering Sans was the easiest way to get what he wanted, it wasn't usually like this – close and careful, and with Papyrus's arms wrapped around him it was almost like an embrace...

Papyrus didn't seem to notice (or care) that Sans was basically unresponsive. He continued talking, almost insufferably pleased with himself. “UNDYNE WAS SO IMPRESSED WITH MY PUZZLE SKILLS THAT SHE ACTUALLY GAVE ME...A GENUINE COMPLIMENT? AND WHEN WE WERE FINISHED, SHE INVITED ME INTO HER HOUSE! I DIDN'T HAVE TO BREAK IN THIS TIME! AND SHE OFFERED ME A MEAL AND WHEN I TOLD HER I DIDN'T TRUST HER NOT TO POISON IT SHE LET ME WATCH HER MAKE IT AND WHEN I ASKED ABOUT HER TECHNIQUE SHE AGREED TO SHARE HER SECRETS WITH ME, SO-”

Sans could barely keep up with the rush of words, finding himself frozen like a computer inundated with too much information. Papyrus carried him down to the living room and finally set him down on the couch, granting Sans a small reprieve. Before he could figure out if escape would be viable or safe, Papyrus was already moving again, bustling into the kitchen which Sans belatedly realised was filled with a haze of smoke. He reeled, wondering if some opportunistic arson had managed to set part of their house on fire, only for Papyrus to reappear carrying a plate and not looking as if anything were amiss. He set one of the plates down on Sans's lap. There was an indistinguishable lump of something in the middle, covered in splashes of black and red and looking as if it had been positively murdered.

“-I MADE SPAGHETTI,” Papyrus finished, and looked at Sans expectantly. It took Sans a long moment to realise that his brother had actually finished talking, and obviously wanted a response of some kind.

Even at the top of his game, Sans wasn't sure he would have been able to figure out exactly how he was supposed to feel about this, so he just latched on to the first coherent thought that managed to take form and ran with it. “That's...amazing, Boss.”

It _was_ pretty damn amazing that not only had his little brother somehow come out of a meeting with Undyne without incurring yet another oblique slight intended to screw them over, but that she had actually given up something – even something as bizarre as a cooking technique – of her own accord. Even more amazing that she'd managed to impart enough of a lesson on Papyrus that he'd been able to come home and replicate it, albeit imperfectly.

Neither brother was especially proficient in the kitchen. Sans's knowledge came more from his days working in the chemistry labs, and his laziness meant that his efforts were half-hearted and often underdone. Papyrus could work the microwave and that had previously been the limit of his skills. Since monster food couldn't spoil, and wasn't harmful even if it was poorly made, it didn't really matter that most of what they ate was just fuel to keep their magic up.

The effort of making something like spaghetti, a meal with multiple parts, crafted with some actual consideration for the texture and taste was...something. Sans wasn't sure what sort of something it was, exactly, but it was definitely _something_.

As stupefied as his response had been, apparently it was the right thing to say because Papyrus somehow managed to beam even harder. There was a buoyant, almost manic energy about him as he pressed a fork into Sans's hand. “EAT IT.”

Sans stared at his brother, and then at the plate. If Papyrus hadn't explicitly told him it was spaghetti, he wasn't sure he could have recognised it. Acrid fumes wafted from the charred, lumpy sauce, making his nasal cavity itch. Sans had pulled food out of dumpsters that looked more appealing, and yet his brother had woken him up at – he discretely checked the clock behind the TV – five in the morning in order to feed him the first meal he'd ever attempted to cook. To share his delighted accomplishment with Sans.

There was really no way he could turn Papyrus down.

Cautiously, Sans loaded some of the stiff, mangled noodles and sauce onto the fork. He tried not to be aware of Papyrus watching him intently as he put it into his mouth. It then took an immense act of willpower not to just spit it straight back out again, his body instinctively cringing and attempting to reject the foreign flavours that definitely didn't resemble anything Sans would call food.

But with Papyrus staring at him, he forced himself to swallow and said, “Wow, Boss. I've...never tasted anything like it.”

Papyrus puffed up in pleasure, easily misinterpreting that as a compliment. “I KNOW. THE GREAT AND TERRIBLE PAPYRUS HAS MANY LAYERS OF RAW, UNTAPPED POTENTIAL. EVEN UNDYNE SAID SO. SHE ALSO SAID IF I WAS INTERESTED, I COULD RETURN FOR ANOTHER LESSON IN ORDER TO ENHANCE MY SKILLS. FINALLY, SHE IS STARTING TO RECOGNISE MY CAPABILITIES.”

“I'll bet,” Sans agreed easily, trying to ignore the queasiness in his gut. Despite its off-putting appearance the spaghetti was actually much more robust than Sans had expected, possibly because Sans was so used to eating low quality meals. Monster food reflected the amount of energy and care that had been put into its making, so even something that tasted god-awful could be full of potent magic under the right circumstances. Apparently Undyne's training had actually imparted something useful to his brother. Even though food had instantly converted into magical energy upon swallowing, however, it didn't seem to be settling quite right. Maybe that was just because of the lingering after-taste.

“THIS WILL BE A TURNING POINT FOR US, SANS,” Papyrus told him. “I KNEW IT WAS ONLY A MATTER OF TIME BEFORE UNDYNE GAVE IN. YOU WILL SEE. OUR POSITION WILL IMPROVE BY LEAPS AND BOUNDS ONCE I AM IN THE GUARD. NO ONE WILL GIVE US TROUBLE ANY MORE. ALL YOU HAVE TO DO IS FOLLOW MY LEAD.”

There was something almost sweet about that sentiment. Sans knew his brother had dreamed of being in the guard for many reasons – for the prestige, the recognition, the power and freedom that came with being at the top of the figurative food chain – but Papyrus had said ' _our_ ' and ' _us_ '. He was thinking of both of them. He was thinking of Sans, even if his older brother was a useless dead-weight most of the time.

And when he spoke, he was looking down at Sans...and more specifically at the collar Sans had forgotten to take off the night before. Sans almost clutched at it self-consciously when he realised. Instead he forced his hand to stay down, fingers clenched with painful tightness around the fork as he nodded stupidly, trying to keep the flustered blush off his face. “Sure, Boss. Whatever you say.”

“GOOD,” Papyrus said, and until that moment Sans hadn't realised there was something...lacking, in Papyrus's stance. Something that had been almost uncertain until Sans had reaffirmed his confidence. Now he looked utterly assured, absently dusting flecks of char off his gloves. “WE'RE GOING TO GET AN EARLY START ON THE DAY. I HAVE PUZZLES TO COMPLETE, AND YOU HAVE HUMANS TO WATCH FOR. WE WILL SHOW UNDYNE THAT WE ARE THE MOST COMPETENT GUARDS IN SNOWDIN. FINISH YOUR BREAKFAST WHILE I FRESHEN UP MY ARMOUR. DON'T TAKE TOO LONG.”

He almost groaned aloud at the thought of having to be outside before he absolutely had to be, but right after agreeing to follow his brother's lead he couldn't very well argue with him. At least with Papyrus gone for the moment he could find some way to discretely dispose of the rest of the pasta instead of forcing it down.

 

* * *

 

If Sans had thought Papyrus was resolved before, it had nothing on his new dedication to his self-appointed puzzle duties in the forest. The next week was spent completely revising the layout of the traps for some level of optimum efficiency that only Papyrus himself understood. Sans quickly learned to stay out of his way or risk getting caught up in his brother's frenzied reworking. It was as if Undyne's small concession towards Papyrus's skill had reignited his desire to impress her, and Sans could only cynically wonder if she'd planned it that way.

Whenever Sans deigned to step away from his post to patrol the area as he was supposed to – which was more of an excuse to stretch his legs than anything – he usually made sure to check in on Papyrus and always found him hard at work, testing gears or setting tripwires. Normally Sans would keep watch for a while, silent and unannounced, hidden close enough to by lulled by the soft grunts and mutterings of his brother without risking being hijacked into doing any actual work himself. He wasn't worried, exactly...just a little concerned that his brother was so caught up in his task that he might overlook something obvious, like the stress he was putting his own body under, or the threat of someone taking advantage of his distraction. 

Though he wasn't sure what he actually expected to do right up until the day someone actually tried to make a move against his brother.  

Sans had been nestled against the base of a nearby tree, listening to the soft huffs of sound as Papyrus worked when it happened. He felt himself go tense and Papyrus froze mid-movement, both of them straining to listen to the quiet rustle of footsteps in snow. Sans carefully peered around the edge of the trunk, watching Papyrus unfold to his full height, the set of his shoulders loose and confident. For a moment he was struck by how intimating his brother looked. His armour may have been home-made, cobbled together from discards found in the dump fitted together by Sans’s ingenuity, but it looked impressive nonetheless. Papyrus cut a formidable figure of black and red against the backdrop of the forest, and for a moment Sans almost felt sorry for anyone who might think they were strong enough to take him. 

Then three distinct figures stepped out of the shadows of the woods, and the bottom dropped out from Sans’s stomach. He should have realised that any opponent would be smart enough to come in force.   
  
“NYEH HEH HEH. SO YOU FINALLY DECIDED TO SHOW YOURSELVES,” Papyrus gloated, sounding unimpressed. “YOUR STALKING TECHNIQUE IS INCREDIBLY POOR. I’VE BEEN FINDING YOUR TRACKS IN THE FOREST FOR DAYS. DID IT TAKE YOU SO LONG TO WORK UP THE COURAGE TO APPROACH ME?”   
  
“Shut it,” one of the monsters growled. All three of them were just as tall as Papyrus, but much bulkier in build as the thick-furred inhabitants of Snowdin tended to be. The monster’s large barrel chest heaved with a pent up, desultory breath. “This is our forest, Skeleton. We don’t want you here.”   
  
“THIS FOREST BELONGS TO THE KINGDOM, AS DO YOU,” Papyrus chided, standing his ground even though the other monsters were slowly advancing on him, circling around the peripheries of his vision. Sans quivered with tension but remained in hiding. He didn’t think they’d noticed his presence yet, which meant they wouldn’t see his attacks coming.   
  
A different monster laughed harshly. “What Kingdom? The monarchy is dead, man. The King doesn’t care about us, and we don’t care about him. It’s survival of the fittest out here, and everyone knows this place belongs to us.”   
  
Papyrus snorted. “THEN CONSIDER YOUR OWNERSHIP REVOKED. I AM CLAIMING THIS FOREST IN THE NAME OF THE GREAT AND TERRIBLE PAPYRUS. I WILL GIVE YOU TWO MINUTES TO REMOVE YOURSELVES FROM MY TERRITORY OR ELSE-”   
  
The last monster who had carefully refrained from drawing attention to itself lunged suddenly, aiming for the blind-spot at papyrus’s back. Its fist slammed into a rising wall of bones, and it reeled back with a screech of pain.   
  
“-I WILL HAVE TO PUNISH YOU FOR YOUR INSOLENCE,” Papyrus finished, undeterred. His scarf swayed majestically in the breeze. It was a good speech. Sans silently applauded it even while he decided he was going to have to have a talk with his brother about dramatic monologuing when monsters were trying to kill him. At the very least, Papyrus should have followed up with another attack on the wounded monster instead of giving it a generous pause in which to recover.   
  
The other two snarled, leaping in tandem. Papyrus braced himself, and for a moment Sans panicked, cursing internally at Undyne’s aggravatingly dangerous lessons about facing one’s enemies head on when Sans had always encouraged his brother to dodge out of harm’s way. For a moment it looked like Papyrus was going to be toppled, but his brother easily turned one of them blue and slammed them back into a nearby tree whilst the other was skilfully tossed over Papyrus’s shoulder and into a nearby snowdrift.   
  
He hadn’t seen his brother in a fight for quite some time, but despite his doubts about Undyne’s questionable training methods that she insisted Papyrus undertake to prove his worth, it actually seemed to have worked. He was faster than he’d ever been when Sans had taught him the basics of battle. His movements were swift and sure, his stance was low and stable, and though Sans thought blue magic might have played a role in the throw, Papyrus made tossing the larger furred monster look positively easy.   
  
Even so, there were three of them, and Papyrus couldn’t keep his eye on all of them at once. The first attacker had rallied themselves to try again whilst Papyrus was still grappling with the one whose soul he’d turned blue. Sans discretely threw a low wave of bones along the ground, knocking the monster off their feet just before they would have made it near his brother’s back. Papyrus started at the unexpected interference, but immediately followed it up with a second wave that sent the monster screeching and tumbling backwards before fearfully turning tail to run. They hadn’t even realised not all the bones had belonged to their victim, but except to the observant both Sans’s and Papyrus’s magic was practically indistinguishable.   
  
“Fuck!” one of the others swore, taking a few steps back, their resolve failing now that one of their buddies had abandoned them. “E-enough! We’re not screwing around!”   
  
“NEITHER AM I,” Papyrus growled, summoning a long, sharpened bone to his hand. Behind his brother’s back, Sans manifested several more in the air to hover threateningly over Papyrus’s shoulder. Sometimes a fearsome show of force was a more effective way to end a fight than winning it; that was how most of his own battles tended to go, at least.   
  
It proved as effective as usual. The two remaining monsters took a good look at the hovering projectiles and decided that perhaps they had made a terrible mistake in bothering this particular skeleton. With a single, meaningful look at each other, they both turned and disappeared into the forest, careful to put lots of trees and barriers between themselves and Papyrus. Papyrus only watched them go, not even moving to take advantage of their vulnerable backsides, which Sans took to mean he really hadn’t had any intention of dusting the intruders in the first place.   
  
For all his skill and fearsomeness, Papyrus was still soft. Sans wasn’t sure if that was more of a relief or a disappointment.   
  
Sans stepped cautiously out of his hiding place once the monsters were well and truly gone, letting his projectiles fade from sight. He didn’t bother disguising his approach as he moved towards his brother’s side. “You know…you probably should have killed them. You could always use the EXP.”   
  
Papyrus turned, hands on hips, but he seemed oddly subdued in the face of his victory. Sans had been expecting a generous self-congratulation or at least some smug assurance that defeat had never been a possibility. “SANS…”   
  
Sans almost flinched when Papyrus put a hand on the top of his skull, some small part of him bracing for his brother to lash out the way he had when he was younger and Sans couldn’t help but interfere in his fights. He knew his brother didn’t appreciate it, but he kept doing it anyway.   
  
But Papyrus didn’t seem irritated this time, though his mouth was turned into a crooked frown as he said, “YOU DIDN’T NEED TO INVOLVE YOURSELF. I COULD HAVE HANDLED THEM ALONE.”   
  
Sans relaxed slightly, shoulders slumping. “Yeah, I know.”   
  
He didn’t say anything else, and for a minute Papyrus didn’t remove his hand either. Sans found it strangely reassuring to simply stand there, the silence oddly comfortable for a change until Papyrus finally broke it by asking, “SHOULDN’T YOU BE AT YOUR POST?”   
  
Sans shrugged with a cheeky grin. “Nah. I’m on break. I should probably get back soon though.”   
  
“MAKE SURE YOU DO,” Papyrus scolded, finally removing his hand and turning away. Sans shook off the unfamiliar sense of yearning. “I DON’T NEED ANY FURTHER DISTRACTIONS. THERE IS MUCH WORK TO COMPLETE!”   
  
“Sure thing, Boss,” Sans said, walking away and vanishing behind a tree. He’d return to his post for a bit, long enough to get absorbed in his work again so he wouldn’t notice if Sans came back to keep an eye on him.


End file.
